55.845 nearest tenth

Consider the KF molecule, which has an ionic bond. The bond length is 2.17 x 1010 m (a) Calculate the energy required to dissoci

Natasha2012 [34]

Answer:

a) +640 kJ/mol or +1.06x10⁻¹⁸ J

b) +276 kJ/mol

Explanation:

To dissociate the molecule, the bond must be broken, thus, it's necessary energy equal to the energy of the bond, which can be calculated by:

E = (Q1*Q2)/(4*π*ε*r)

Where Q is the charge of the ions, ε is a constant (8.854x10⁻¹²C²J ⁻¹ m⁻¹), and r is the bond length. Each one of the ions has a charge equal to 1. The elementary charge is 1.602x10⁻¹⁹C, which will be the charge of them.

1 mol has 6.022x10²³ molecules (Avogadros' number), so the energy of 1 mol is the energy of 1 molecule multiplied by it:

E = 6.022x10²³ *(1.602x10⁻¹⁹)²/(4π*8.854x10⁻¹²*2.17x10⁻¹⁰)

E = +640113 J/mol

E = +640 kJ/mol

Or at 1 molecule: E =640/6.022x10²³ = +1.06x10⁻²¹ kJ = +1.06x10⁻¹⁸ J

b) The energy variation to dissociate the molecule at its neutral atoms is the energy of dissociation less the difference of the ionization energy of K and the electron affinity of F (EA):

498 = 640 - (418 - EA)

640 -418 + EA = 498

222 + EA = 498

EA = +276 kJ/mol

8 0

4 years ago

Indicate whether the following balanced equations involve oxidation-reduction. Check all that apply. Check all that apply. 2H2SO

guapka [62]

Answer : The balanced equations involve oxidation-reduction are:

(a) $2H_2SO_4(aq)+2NaBr(s)\rightarrow Br_2(l)+SO_2(g)+Na_2SO_4(aq)+2H_2O(l)$

(b) $3SO_2(g)+2HNO_3(aq)+2H_2O(l)\rightarrow 3H_2SO_4(aq)+2NO(g)$

(c) $NaI(aq)+3HOCl(aq)\rightarrow NaIO_3(aq)+3HCl(aq)$

Explanation :

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

(a) The given chemical reaction is:

$2H_2SO_4(aq)+2NaBr(s)\rightarrow Br_2(l)+SO_2(g)+Na_2SO_4(aq)+2H_2O(l)$

This reaction involve oxidation-reduction reaction because the oxidation state bromine changes from (-1) to (0) which shows oxidation and sulfur changes from (+6) to (+4) which shows reduction.

(b) The given chemical reaction is:

$3SO_2(g)+2HNO_3(aq)+2H_2O(l)\rightarrow 3H_2SO_4(aq)+2NO(g)$

This reaction involve oxidation-reduction reaction because the oxidation state sulfur changes from (+4) to (+6) which shows oxidation and nitrogen changes from (+5) to (+2) which shows reduction.

(c) The given chemical reaction is:

$NaI(aq)+3HOCl(aq)\rightarrow NaIO_3(aq)+3HCl(aq)$

This reaction involve oxidation-reduction reaction because the oxidation state iodine changes from (-1) to (+5) which shows oxidation and chlorine changes from (+5) to (-1) which shows reduction.

(d) The given chemical reaction is:

$PBr_3(l)+3H_2O(l)\rightarrow H_3PO_3(aq)+3HBr(aq)$

This reaction does not involve oxidation-reduction reaction because the oxidation state of element present on reactant and product side are same.

3 0

3 years ago

How many molecules of oxygen are there in 1.00 dm3 of oxygen at standard pressure and a temperature of 273 K. Give your answer t

rewona [7]

Pressure=p=1atm
Temperature=T=273K.
V=1dm^3=1L

we need no of moles

$\\ \tt\hookrightarrow PV=nRT$

$\\ \tt\hookrightarrow n=\dfrac{PV}{RT}$

$\\ \tt\hookrightarrow n=\dfrac{1}{273(8.314)}$

$\\ \tt\hookrightarrow n=1/2269.7=0.0004mol$

No of molecules=No of moles×Avagadro no

$\\ \tt\hookrightarrow 0.0004(6.023\times 10^{23})$

$\\ \tt\hookrightarrow 2.4\times 10^{20} molecules$

5 0

2 years ago

Read 2 more answers

Draw a Lewis dot structure of the bonds between atoms in a molecule of this product. Use a - (dash) to represent a bonding pair.

Alina [70]

Ensure O has stable octet configuration

3 0

3 years ago

An atom has 30 protons, 21 neutrons, and 19 electrons. Is this an ion? If so, what type of ion is this?

marissa [1.9K]

Answer:

An atomic number

Explanation:

If a neutral atom has 30 protons and 34 neutrons, the number of electrons in the atom is: A) 94. B) 34. 64. ... 17) What is the symbol for the ion with 19 protons and 18 electrons? A) F+. B) K+ ... 21) Identify the metalloid in the following list. Hope this helps you! Ask me anything if you have any quistions!

7 0

4 years ago